Drafting apparatus.



H. W. ARMSTRONG.

DRAFTING APPARATUS.

APPLICATION FILED ocT.1,I9I4.

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AHarneyjwnsTnoPP ARMSTRONG, or HAMILTON, ONTARIO, CANADA.

DRAFTIN'G APPARATUS.

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To all whom t may concern.'

`Be it known that I, HARRY WEsTRoPP ARMSTRONG, a subject of the Kingv of Great Britain, residing at 39 Duke street, in the city of 'Hamiltoxn county of Wentworth, Province of Ontario, Canada, haveinvented certain new and useful Improvements in Drafting Apparatus, of which the followingl is a specification. ,Y

In making of mechanical, architectural and other drawings, extensive `surfaces require to be covered with section lining or other conventional details indicating the materiahsurface finish, ornamentation, and the like. All this at resent is drawn by hand, using pen or pencll, which involves the expenditure of a large amount of time.

My object is to devise means whereby such conventional details may be .rapidly and effectively filled in without'the necessity of drawing in each mark or line by pen or pencil. i 1

I accomplish my object by providing a series ofplates, preferably of some stiff Hexible material, each plate having formed thereon in strong relief a positivei representation of draftsmans conventional detail work, each differing in the character of the representation thereon. These plates are used by placing them under-the tracing paper or linenon which the drawing is being made, and by taking an impression of the raised design by rubbing the surface of the drawing with ycrayon or pencil. y

The details of the process arev hereafter more specifically described, and the apparatus and work done thereby are illustrated in Ithe accompanying drawings in which- 1 wall of a building showing details which may be produced by my device; Fig. `2 a cross section of the same wall; Figs. 3`and 4 plan views of two of the plates constructed in accordance with my invention; Figs. 5 and 6 plan views of similar plates provided with means for joining them side by side; Figs. 7 8 and 9 cross sections on an exaggerated scale showing different forms of section for the raised lines on the plates; and Fig. 10 a perspective view of a clip used for joining two plates together.

In the drawings like numerals of reference indicate corresponding parts in the different figures.

. l are the plates, which are preferably of some stiffI moderately4 hard and moderately Specification of Letters. Patent. Pgpbntgd Jun@ 20, 1191MB, Application filed October 16, 1914. Serial-No. 866,965.

thickdmaterial. While a good quality of fr cardboard or any other material possessing the necessary characteristics is more or less satisfactory, Celluloid or xylonite will usually be employed. Each plate has formed thereon in strong relief a representation of conventional detail work such as employed by draftsmen.

By conventional detail work isto be understood any design that requires to be constantly repeated to indicate diHerent classes of material and surfaces of same, such as brickand stonel work, concrete, timber, etc., in section, plan and elevation, shading such as used to. represent curved surfaces, and all repeated designs or ornamentations. For example, in Fig. 3 'is represented section lining such as commonly ,employed to indicate sections of glass, brick or stone. In Fig. 4 is represented a brick surface, Fig. 5 a surface shading of parallel lines such as may be employed on stone surfaces, and in Fig. 6 is represented concrete work in section. .A It will be noted that the design on each plate is a positive, .that is, it corresponds exactly with the reproduction instead of being 'a negative like an electrotype with the design reversed as to position as in a photographic negative.

`The raised lines are preferably formed without` producing corresponding depressions on the back of the late, thatis to say, the designs are preferably not embossed, but will be applied to the surface ofthe plate so that the 'back of any4 plate is a plane surface. When so constructed the y raised lines possess a very desirable rigidity re 1 shows a face view of, part o'f a In cross section the raised parts may vary accordin to the nature of the representation. For ne section lining, for example, the section maybe triangular as shown in Fig.- 7 for sharp clear heavy section lining the quadrilateral form shown in Fig. 8 may be employed, the angles being sharp, and for soft effects rounded corners may be employed as shown in Fig. 9.

It is found in practice that the relief of the design should not be less than 1/100 of anl inch and that all parts of the face of the design should reach substantially the same plane, so that ad'acent lines are substantially the same dis ance from the back of the plate. Each plate is Surrounded byl a plain margin or border almost flush with or at any rate but slightly below the sur- .an'd stiffness.

face ofthe-design, which is of importance. as it prevents the edges of the design being chipped and supports thetracin paper beyond the design so that no ten ency exlsts for ythe edges of the design to be brought out too prominently during the rubbing process. c j n l c The plates are-employed by bringing one ofappropriate design below the part of the drawings to which the design is to'be applied. An oil crayon isv then rubbed over the surface of the drawing paper, whereupon the design appears on the surface of the paper rubbed. Any light transference ofthe crayon which may take place between the lines may then readily be removed by lightlyl rubbing with a suitable drawing cleaning rubber. A roller of'said composi- V 'y tion is lfound tobe most satisfactory for removing such superfluous matter. 'There is then left onk the drawing a clear representa- 'tion 'of the -desired]details, slightly fainter, y'however, than the ink drawn lines of the drawing. "The sectional and surface repres'entationsvare thus slightly subordlnate to the outlines, lwhich isavery desirable feature, 'particularly in architectural work. InI order to enable the'plates to be moved readily beneath a` large drawing,each plate is preferably provided with small piecesV 2 lof a, magnetic'fmetal such as ironor steel. These are embedded or otherwise secured in the'fplates,l preferably` at each side,- and are spaced so that any pair may be attracted by the polesy of a horse shoe magnet acting through the drawing from above. To'facilitate the plates beingeasily moved by such meansA they areprovided both on theirtop and bottom surfaces with small raised knobs, one in each corner, which reduces friction with thev paper above"v and the table beneath. p It will sometimesbe necessary to lit two or'more plates together 'so that different position.

representations may be reproduced exactly iitted to 'one anotherV in a predetermined y For this purpose certain ofthe plates may have the' representation carried right out to one edge, as shown `in Figs. V5 and 6,'and the edges of the plates designed to fit together provided with suitable means for connecting the plates in the desired relationship. In vthese figures of the drawings, I- show bent clips 3 secured to the l.

edges of one of the platesin such a manner that the edges of the adjacent plate may be slipped in to them. Any other means, of course, may be provided for this urpose.

V To facilitate the lifting of t e plates, thumb notches 4 are provided preferably one` at each side of eachvplate. The plates, for .indexing purposes, are numbered at their upper right hand corners so that they may be readily kept in a card file for convenient access.

It will be understood of course that there is no limit to the different representations that may be applied'to plates. A complete set will -necessarily contain similar representations onvdifferent scales. vDifferent sets may also be' rovided according to the class of drawingA or'which it is to be'used, an architects set differing from that supplied for .the use of a mechanicalfdraftsman.

What I claim as my invention is 1. Drafting apparatus comprising a stiff hard plate havingformed thereon raised lines iny strong relief formin a positive rrepresentation of draftsmans conventional detail work surrounded by a plain border adapted to form a-support for superimposed tracing material beyond the margins of the design.

2. Drafting apparatus Comprisinga series of stiff hard plates each having formed thereon in stron relief a positive representation of dra tsmans conventional detail work` surrounded by a plain border adapted to form a `support or superim posed tracing material eyond the margins of the design and each diering in the character of the representation thereon.

3. Drafting apparatus comprising a stiff hard plate wlth a plane back having formed NORMAN R. TYNDALL,

GEO. P. MACKIE. 

